Histogram error

Newbie
1

I’m trying to draw two histograms (h1) on the same canvas from two different root files(1.root and 2.root). I used two macros (1.C and 2.C) but both are resulting in error.
I’m attaching root files.
1.root (36.8 KB) 2.root (37.0 KB)

Macro files used:
1.C

{
    
    TFile *f1 = TFile::Open("1.root");
    TH1D *h1= (TH1D*)f1->Get("h1");
    h1->Draw("hist l");
    h1->SetLineWidth(3);
    h1->SetLineColor(2);
    
    TFile *f2 = TFile::Open("2.root");
    TH1D *h2 = (TH1D*)f2->Get("h1");
    h2->SetLineWidth(2);
    h2->SetLineColor(4);
    h2->Draw("hist l same");
    
}

2.C

{


TFile *f2 = TFile::Open("1.root");
TCanvas *c2 = (TCanvas*)f2->Get("h1");
h1->Draw("hist same");
h1->SetName("aa");
aa->SetLineStyle(7);
aa->SetMarkerStyle(23);
aa->SetLineColor(4);
aa->SetLineWidth(2);

TFile *f3 = TFile::Open("2.root");
TCanvas *c3 = (TCanvas*)f3->Get("h1");
h1->Draw("hist same");
h1->SetName("in");
in->SetLineStyle(9);
in->SetMarkerStyle(20);
in->SetLineColor(2);
in->SetLineWidth(2);



leg = new TLegend(0.51,0.69,0.9,0.9);
   leg->SetHeader("beam");
   leg->AddEntry(in,"2","l");
   leg->AddEntry(aa, "1","l");
   leg->SetFillColor(10);
   leg->Draw();

}

Error:

error_1
error_11826×621 146 KB

I dont know what causing an error (possibly different y axis range) because these macro file works fine with other files having same parameter.

Looking forward to hearing from expert root users.

ROOT Version: 6.14.06
Platform: Ubuntu/Linux
Compiler: Not Provided

2

In your root files, the histograms are called 1, 2,…, not h1, h2,…

TH1D *h1= (TH1D*)f1->Get("1");
3

Hi,

You have several problems in the macros.
Here is modified code for 1.C

{
TFile *f1 = TFile::Open("1.root");
TH1D *h1= (TH1D*)f1->Get("1");
h1->SetLineWidth(3);
h1->SetLineColor(2);
h1->Draw("hist l");

TFile *f2 = TFile::Open("2.root");
TH1D *h2 = (TH1D*)f2->Get("1");
h2->SetLineWidth(2);
h2->SetLineColor(4);
h2->Draw("hist l same");
}

And 2.C:

{
TFile *f2 = TFile::Open("1.root");
TH1 *h1 = (TH1*)f2->Get("1");
h1->SetName("aa");
h1->SetLineStyle(7);
h1->SetMarkerStyle(23);
h1->SetLineColor(4);
h1->SetLineWidth(2);
h1->Draw("hist");

TFile *f3 = TFile::Open("2.root");
TH1 *h2 = (TH1*)f3->Get("1");
h2->SetName("in");
h2->SetLineStyle(9);
h2->SetMarkerStyle(20);
h2->SetLineColor(2);
h2->SetLineWidth(2);
h2->Draw("hist same");

leg = new TLegend(0.51,0.69,0.9,0.9);
leg->SetHeader("beam");
leg->AddEntry(h1,"2","l");
leg->AddEntry(h2, "1","l");
leg->SetFillColor(10);
leg->Draw();
}

Regards,
Sergey

4

Thank you so much. :slight_smile:

5

Thank you for pointing my silly mistake. :grinning:

6

I included 2 more root files that have a high range of Y-axis. The full histogram is not confined in canvas and the upper part of the histogram is cut. How this problem can be resolved?
Root files (4)
1.root (36.8 KB) 2.root (37.0 KB) 3.root (36.0 KB) 4.root (35.3 KB)

Macro file used

{

TFile *f1 = TFile::Open(“1.root”);
TH1D h1= (TH1D)f1->Get(“1”);
h1->SetLineWidth(3);
h1->SetLineColor(2);
h1->Draw(“hist l”);

TFile *f6 = TFile::Open(“2.root”);
TH1D h6 = (TH1D)f6->Get(“1”);
h6->SetLineWidth(2);
h6->SetLineColor(94);
h6->Draw(“hist l same”);

TFile *f4 = TFile::Open(“3.root”);
TH1D h4 = (TH1D)f4->Get(“1”);
h4->SetLineWidth(2);
h4->SetLineColor(8);
h4->Draw(“hist l same”);

TFile *f5 = TFile::Open(“4.root”);
TH1D h5= (TH1D)f5->Get(“1”);
h5->SetLineWidth(3);
h5->SetLineColor(9);
h5->Draw(“hist l same”);

leg = new TLegend(0.51,0.69,0.9,0.9);
leg->SetHeader(“Energy deposition”);
leg->AddEntry(h1,“1”,“l”);
leg->AddEntry(h4, “4”,“l”);
leg->AddEntry(h5,“5”,“l”);
leg->AddEntry(h6, “6”,“l”);
leg->SetFillColor(10);
leg->Draw();

}

result_canvas

Waiting for the kind reply.

7

You should first draw histogram with maximal amplitude.
Or use THStack class which does proper alignments automatically.

8

Thanks, drawing the histo of maximum amplitude resolved the problem. :grinning:

9

Not that using THStack would be simpler/safer in your case. THStack computes the full range containing all histograms. You do not need to know which histogram has the bigger amplitude